Should the Rangers sweep, they are the American League West champions. Should they win three of four, they clinch no worse than a tie for the AL West title. Should the Rangers do less, then that's where the final week of the season could get interesting.
"We're not looking too much further ahead than Monday," third baseman Adrian Beltre said after his current team beat his old one. "We just want to finish with a nice push."
The A's also won Sunday, getting out of Yankee Stadium with a win to remain four games out of first.
"Monday is our only focus," closer Joe Nathan said after the Rangers reached the 90-win mark in the club's 152nd game, the quickest any Rangers team has ever gotten to 90 wins.
But as manager Ron Washington said, "It's not about the wins now; it's about getting to the playoffs."
Texas got one step closer when Nathan got Franklin Gutierrez to strike out to end the game with the tying run at second base. That performance came on top of a gritty effort by Mike Adams, who had to pitch out of a gnarly eighth inning in which the Mariners had the bases loaded with one out.
"That was the game right there," Beltre said. "They were one hit away from [a series sweep]."
Adams gave up singles to Gutierrez and Kyle Seager to open the eighth with the Rangers up by one, then a grounder from John Jaso moved the runners to second and third. Washington had Adams intentionally walk Justin Smoak, the former Rangers prospect who had five hits in the first two games of the series, loading the bases.
Washington, perhaps in a preview of how he will use his bullpen in the postseason, never thought about making a change, saying "[Adams] is my guy in the eighth inning."
As for Adams, it was just one more game when he didn't make it easy on himself.
"I was thinking, 'Well, here we go again,'" the veteran said. "I'd like to have clean innings, but sometimes they're tough to come by."
Eric Thames, whose homer in the seventh inning got Seattle its first run off winning pitcher Ryan Dempster (12-7), had a chance to tie the game but he struck out on a 1-2 pitch. Rookie DH Luis Jimenez then popped out, preserving the Texas lead.
"It's all about focus," Adams said. "In situations like that, you'd better get aggressive, because if you think the worst, that's what will happen."
Much of the Rangers claiming their 90th win rests with Dempster, who has been a fountain of wins since coming from the Cubs to the Rangers. Sunday was his 10th start for Texas. He's won seven of the 10, and on Sunday threw shutout ball until the seventh, when Thames and then Brendan Ryan homered.
"Dempster was really good," Seattle manager Eric Wedge said. "He kept us off balance all day long. I mean, he's a veteran pitcher. He knows how to get big league hitters out. I thought he was really good today."
And now it's back home for the Rangers, who play seven of their final 10 games in Arlington, three against the third-place Angels after the four-game set with Oakland. Texas would like to get what would be its third consecutive AL West title sewn up before finishing the season with a three-game set in Oakland.
"These are big games," shortstop Elvis Andrus said. "We're ready. We're glad to be playing at home."
The Rangers have played 12 games against the A's and each side has won six times. Texas, which had lost just one series in the last month before dropping two of three in Seattle, hopes to get Josh Hamilton back in center field sometime during the series. Oakland has been in a bit of a slump, losing five of its last six games before beating New York in Yankee Stadium on Sunday.
"All our focus is on Oakland," Washington said.
The A's focus is certainly reciprocal.